The present invention relates to sewing apparatus, and particularly to automatic sewing apparatus of the computerized type especially useful in the footwear and garment manufacturing industries.
The currently-used computerized sewing apparatus generally includes X-Y servo systems for controlling the movement of the workpiece along the X- and Y-coordinates, and for controlling the sewing head drive. However, the known systems generally require complex clamping devices for moving the workpieces with respect to the sewing head, and for retaining them in place and in fixed shape during the sewing operations. Such complex clamping devices are quite costly and time-consuming to produce. A further drawback in the current computerized sewing systems is that the workpiece itself is not always accurately cut so that the stitching applied to the workpiece may not present the best appearance. This is particularly true when the stitching is applied along the edge of the workpiece, as is frequently done in the garment and footwear industries.
U.S. Pat. No. 4,498,404 discloses one form of automatic sewing apparatus directed particularly to improving the above drawbacks. The sewing apparatus therein described obviates the need for complicated clamping arrangements by including a suction head type manipulator, and improves the appearance of the stitched workpiece by providing an optical device for optically detecting the edge of the workpiece to receive the stitches.